Design Progress for the National Ignition Facility Laser Alignment and Beam Diagnostics

Earlier papers have described approaches to NIF alignment and laser diagnostics tasks. 1,2,3 Now, detailed design of alignment and diagnostic systems for the National Ignition Facility (NIF) laser is in its last year. Specifications are more detailed, additional analyses have been completed, Pro-E models have been developed, and prototypes of specific items have been built. In this paper we update top level concepts, illustrate specific areas of progress, and show design implementations as represented by prototype hardware. The alignment light source network has been fully defined. It utilizes an optimized number of lasers combined with fiber optic distribution to provide the chain alignment beams, system centering references, final spatial filter pinhole references, target alignment beams, and wavefront reference beams. The input and output sensors are being prototyped. They are located respectively in the front end just before beam injection into the full aperture chain and at the transport spatial filter, where the full energy infrared beam leaves the laser. The modularity of the input sensor is improved, and each output sensor mechanical package now incorporates instrumentation for four beams. Additional prototype hardware has been tested for function, and lifetime tests are underway. We report some initial results.